This invention relates to manual line graphics editing, particularly as applied to real-time applications, such as used for segment selection of an intravascular ultrasonic image. This invention applies specifically to closed contour editing for defining a boundary on a cross-sectional plane of a vascular image.
Manual editing is a very useful tool in medical imaging, especially when segmentation is needed to obtain measurements. Because no suitable automated methods are available to detect segments of medical images in known medical imaging systems, reliance on manual tracing is needed.
Manual editing is also very important for automated detection requiring observer supervision. In particular instances, there is a need to manually edit portions of the computer detection for further analysis.
Several manual editing methods are currently available for drawing closed contours. In one known method, a user can draw the contour using a computer mouse or other drawing device. During the tracing, the user must erase part or all of the drawing through a continuous process of deleting the current end point of the drawing. Once the drawing is completed, no modification is allowed except the deletion of the entire contour. In other known methods, the contour is segmented among a set of control vertices. By pulling the vertices, the user can adjust the contour locally. More vertices may be inserted while redundant vertices may be removed. Although this method provides the ability to change the contour, it requires substantial amount of user interaction.
Another method allows the user to indicate two points on the contour after which the user first deletes the segment to be changed and then draws the new segment. This method requires still additional interaction, and the user cannot compare the new segment with the old segment.